.h5{
    height:100%;

}
.h5_page{
    position: relative;
    width:100%;
    height:100%;
    background-color: #ddd;
    background-size: 100%;
    background-repeat: no-repeat;
}
.iphone{
    width:340px;
    height:540px;
    background-color: #fff;
    position: absolute;
    background-color: #fff;
    left:50%;
    top:50%;
    margin:-270px 0 0 -170px;
}